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Qt 4.7 debuts QML for declarative UI development

The Qt developers have announced a technical preview for QT 4.7, the cross platform C++ framework for GUI applications. According to the developers, the pre-release is not suitable for production use, but will give a good idea of how they plan to enhance the framework. According to the developers, the final release of Qt 4.7 will be around the middle of the year.

The major highlight of the release is the incorporation of Qt Quick, the Qt UI Creation Kit, which allows application developers to declaratively define their user interfaces in QML. The QML is then processed at run time by QtDeclarative to render the user interface and bind the interfaces components with the underlying C++ application logic. Tutorials and examples for QML are available which demonstrate how QML can incorporate JavaScript code as part of the UI declaration, allowing for a more effective separation of interface and application logic.

Other new features of Qt 4.7 are the Bearer Management API and Multimedia API. The Bearer Management API, implemented in the QtNetwork module, allows applications to identify if a system is online, identify, start and stop network interfaces and manage transparent roaming between access points. A QtNetworkAccessManager class makes use of this functionality to provide HTTP level roaming, ideal for mobile applications. The Multimedia API supports the playback of audio and video within an interface and has been integrated with Quick.

An alpha version of the Qt Creator 2.0 IDE, with support for QML including auto-completion and syntax awareness in the editor and QML previewing and debugging, is also available. More details of the new features can be found on the "What's New in Qt 4.7" page and the preview version of the LGPL licensed framework is available to download.

Qt is a framework written in C++ available for Linux, Windows and Mac OS X, which offers the same functions on all three platforms. It forms the basis for the open source KDE Linux desktop. After taking over Trolltech, the company that originally developed the framework, Nokia released the library under the LGPL and provided open access to the code repositories.